a prospective, open label study of human t cell responses to live attenuated japanese encephalitis vaccine sa14-14-2

Conditions: Japanese Encephalitis; Japanese Encephalitis Vaccine

Summary: japanese encephalitis (je) live attenuated vaccine sa14-14-2 has been in use for more more than 20 years in asia. je vaccine sa14-14-2 is licensed in india and has been widely used since 2006. je vaccines give protection by generating a neutralizing antibody response, but both naturally exposed persons and patients with je also have t cell responses. whether je vaccine sa14-14-2 elicits t cell responses is unknown. this study tests the hypothesis that t cell responses are generated in response to je sa14-14-2 vaccination. the aim of this study is to characterize t cell responses to je vaccine sa14-14-2 in healthy people, and to investigate differences in t cell responses between natural exposure, vaccination and disease.


Eligibility criteria:
inclusion criteria: * a male or female adult between 18 and 50 years of age. * written informed consent. * free of obvious health problems as established by medical history and history- directed physical examination before entering the study. * expected continuous residence in india during study period, without travel outside india * an efficacious method of contraception must be used during the study for women of childbearing potential. exclusion criteria: * use of any investigational or non-registered drug or vaccine other than the study vaccine within 30 days preceding administration of sa14-14-2 vaccine, or planned use during the study period. * chronic administration of immunosuppressants or other immune-modifying drugs within a period of six months before vaccination or at any time during the study period. * any confirmed or suspected immunosuppressive or immunodeficient condition. * a family history of congenital or hereditary immunodeficiency. * any antiviral drug therapy within a period of six months before vaccination or at any time during the study period. * history of significant allergic disease or reactions likely to be exacerbated by any component of the study vaccine, especially allergic disease or reactions to any previous dose of any vaccine. * history of having received je vaccine, yellow fever vaccine, tick-borne encephalitis vaccine or experimental flavivirus vaccine. * history of documented je infection. * detectable anti je or west nile neutralizing antibodies in screening tests. * acute disease at the time of enrollment. entry into the study may be deferred until the illness is resolved. * acute or chronic, clinically significant, pulmonary, cardiovascular, hepatic, neurological or renal functional abnormality, as determined by history and physical or laboratory examination that is not controlled by drugs. * administration of immunoglobulins and/or any blood products within the three months preceding administration of vaccine, or planned administration during the study period. * seropositive for hiv, hcv or hbsag. * lactation, pregnancy or intention to get pregnant. * history of excessive alcohol consumption, drug abuse or significant psychiatric illness. * any other condition that in the opinion of the investigator would pose a health risk to the participant or interfere with the evaluation of the vaccine.

Keywords: japanese encephalitis japanese encephalitis vaccine t lymphocyte immune response